1. Field of the Invention
The present invention relates to a vehicular lamp with a lens attached to a lamp body by laser welding and a method of manufacturing same.
2. Background Art
A vehicular lamp, such as a headlamp for a motor vehicle, is configured to dispose a bulb as a light source and a reflector in a lamp chamber, which is formed by attaching a lens to a front opening of a lamp body. For a configuration in which the lens is attached to the front opening of the lamp body, the prior art has used a laser welding method or the like. Patent Document 1 discloses a laser beam receiving surface is configured in a flange-like shape to protrude outwardly so that the receiving surface can receive a laser beam coming from an oblique direction with respect to a direction where the lens is mounted on the lampbody, which passes through the flange-like shaped portion of the lens.
Specifically, as shown in FIG. 10, the laser welding is applied to the area where an abutment surface 231A at an end of a seal leg 23A of a lens 2 abuts on an abutment surface 121A of a peripheral wall 12A of a lamp body 1A. A laser beam receiving surface 25A that protrudes outward is formed on a top edge of the seal leg 23A to receive the laser beam L projected onto the laser beam receiving surface 25A from an outside of the lens 2A to the abutment surface 121A of the lamp body 1A such that the abutment surfaces 121A and 231A of the lens 2A and the lamp body 1A are laser welded. By way of this configuration, as described in Patent Document 1, compared with the conventional manner that the laser welding process is performed by projecting the laser beam onto the abutment surface while transmitting it through the seal leg along the abutment surface, the disclosed art allows an optical path length that the laser beam transmits through the lens to be shortened. Accordingly, it may be possible to preferably perform laser-welding and avoid loss of the laser beam energy on the abutment surfaces.
[Publication 1] JP-A-2001-243811
In Patent Document 1, the laser beam receiving surface is configured to protrude beyond the outer surface of the seal leg of the lens. When the lens is seen from the front, the laser beam receiving surface appears to protrude from the periphery of the lens. Accordingly, an outside dimension of the lens, i.e., the outside dimension of the lamp, becomes large. Further, when the welded surface between the lens and the lamp body is seen from the front through the lens, it appears dark. Because width dimensions of the laser welded surface (i.e., dimensions in a direction of the thickness of the seal leg) enlarges due to forming the laser beam receiving surface, the dark portion with larger width come out from the outer edge of the lens, and thereby the appearance of the lamp deteriorates. Further, a metal molding structure employed for forming the lens having the laser beam receiving surface configured to protrude beyond the outer surface of the seal leg may be complicated. Thus, this creates rising cost.
An object of the present invention is to provide a lamp with an improved appearance by reducing the dimensions of a laser-welded surface in a direction of its width and a method for manufacturing the lamp.